Now, spikes are a source of "found" steel that makes sense. RR spikes are reliable, available, and workable.
Even though the vast majority of spikes are driven by track laying machines, the image of a long row of swarthy men swinging 9# hammers is part of the mystique of spike art pieces.
I especially like to make Frederick's crosses.
(F,C,F,Dm7,repeat) Oh, John Henry when he was a little baby,.....Sittin' on his Pappy's knee,......... Hit it Tai. Lets see a youtube of ukulele John Henry video.